A multi-antenna technology is widely used in a current communications system, so as to enhance a system capacity or improve user experience. For example, a 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) R8 system may support four antenna ports, and an LTE R10 system may support eight antenna ports. However, an existing LTE R10 system supports sending of a maximum of two transport blocks (TB), and each TB on which channel coding has been performed is referred to as a codeword (CW). Therefore, in the current system, a maximum of two CWs need to be mapped to a maximum of four layers or a maximum of eight layers. In addition, the existing system feeds back a channel quality indicator (CQI) for each CW. The CQI may be used to indicate a corresponding modulation and coding scheme (MCS) when a block error rate of a TB corresponding to the CW is not less than a specified threshold (for example, 10%) when the TB is transmitted by using a data channel. The MCS indicated by the CQI has an equivalent signal to interference plus noise ratio (SINR) interval, that is, it may be understood that each CQI corresponds to one SINR interval.
The existing system supports a maximum of two CWs and feeds back only one CQI for each CW, and a maximum of four or eight layers may be used during channel transmission. Therefore, each CQI needs to reflect channel quality of multiple layers. Data transmission is scheduled by a base station according to a CQI fed back by user equipment. Therefore, when the CQI reflects more layers, accuracy of scheduling becomes lower, and consequently, precision of an MCS used during data transmission is lower; and less user equipment is paired during implementation of multi-user multiple-input multiple-output (MU-MIMO) transmission, and consequently, a throughput of a communications system is lower.